One embodiment of the invention relates to a functional module, another embodiment relates to a wiring module and another embodiment relates to a modular wiring system having locking elements. Other patents which may relate to any one of the embodiments listed below are: U.S. Pat. No. 7,955,096, which issued on Jun. 7, 2011; U.S. Pat. No. 7,666,010 which issued on Feb. 23, 2010; U.S. Pat. No. 7,357,652 which issued on Apr. 15, 2008; or, design patent nos. U.S. D618,627 which issued on Jun. 29, 2010; U.S. D616,831 which issued on Jun. 1, 2010, wherein the disclosures of these patents are hereby incorporated herein by reference.